; enable long mode
   mov ecx, 0xc0000080 ; set the C-register (EFER MSR)
   rdmsr
   or eax, 1 << 8; set LM-bit
   wrmsr

   ; set cr3 to point to page table
   mov eax, PHYS(init_pml4)
   mov cr3, eax

   ; enable paging
   mov eax, cr0
   or eax, 1 << CR0_PAGING_ENABLE_BIT
   mov cr0, eax

   ; load the 64-bit GDT
   lgdt [PHYS(gdt.gdtr)]
   jmp KERNEL_CODE_SELECTOR:PHYS(long_mode)